The major aim of the research is to establish that the infant and young child share with others what they see and find in their environments. Since they display these behaviors as early as 12 months of age--long before children are exhorted by their parents to share-- their occurrence forces a new view of the infant and young child. Since sharing is a valued social behavior, its common but heretofore unremarked appearance constitutes a developmental milestone. The research is directed toward identifying the behaviors of sharing, namely showing objects to others, giving them, and then engaging in partner- play (playing with the given object while it is still in contact with the recipient); discovering the characteristics of objects that prompt sharing, as well as the effect on sharing of the recipient's behavior (evoking, reinforcing, and modeling). The studies will be carried out in the laboratory, homes, and day-care centers. In the latter two settings, attention will be directed toward the earliest manifestations (the ontogeny) of the separate responses as well as toward the responses of recipients, especially of peers and siblings, that may inhibit them.